How are void levels in compacted Superpave specimens determined?

• A. By measuring the temperature of the mix
• B. By comparing Bulk Specific Gravity to Maximum Specific Gravity
• C. By assessing the weight of the mixture
• D. By testing the moisture content of the aggregate

Answer: (B)

Determining void levels in compacted Superpave specimens is a critical part of assessing the quality and performance of asphalt mixtures. The correct approach involves comparing the Bulk Specific Gravity to the Maximum Specific Gravity of the asphalt mixture.

Bulk Specific Gravity refers to the density of the compacted asphalt mixture, while Maximum Specific Gravity represents the density of the asphalt when it is completely solid without any voids (air or water). By comparing these two values, one can calculate the volume of voids present in the compacted material. The concept relies on the relationship between the specific gravities; a lower Bulk Specific Gravity indicates a higher volume of voids within the specimen.

This process is essential since the volume of voids impacts the performance characteristics of the asphalt, including its durability and resistance to deformation. A correct understanding of void levels helps ensure that the mixture will perform well under traffic loads and environmental conditions.

In contrast, measuring the temperature of the mix, assessing the weight of the mixture, or testing the moisture content of the aggregate do not directly provide insights into the void levels within the compacted specimen. These factors may influence the overall performance of the asphalt mixture, but they do not specifically determine void content in the same way the comparison of Bulk Specific Gravity